Acacia mangium tannin functionalized graphene nanoplatelets produced via ball-milling for sustainable soy protein-based film

A simple and green natural spider silk inspired strategy is proposed for fabricating advanced soy protein (SP)based film by introducing Acacia mangium tannin (AMT) functionalized graphene nanoplatelets (AMT-GnPs), greenly and cost-effectively produced via ball milling graphite with AMT. The prepared film, namely SPEI/GnPs, exhibited noticeable improvement in mechanical properties over the neat SP-based film such as tensile strength (11.60 vs. 2.19 MPa) and toughness (21.12 vs. 3.09 MJ m-3). In addition, such developed biomimetic film still exhibited a high strain at failure (220.3%). The outstanding performance was attributable to the formation of dense interfacial covalent and H-bonding interactions between the scattered AMT-GnPs and the protein matrix. Moreover, after incorporating AMT-GnPs, the SPEI/GnPs film featured excellent UV-blocking performance and good water resistance. Overall, this study offers a facile biomimetic strategy for strong, tough, and biodegradable films for many potential applications like packaging and UV-blocking bioproducts.